How Genetics Affects Your Decision Making

Neuroeconomics, a relatively new branch of science, is slowly unraveling how specific gene variations influence how we make decisions.

Genes are units of information within cells that transmit characteristics, such as hair or eye color, from one generation to the next. Genes also provide instructions for cellular activity and play a role in behavior. Sometimes genes develop mutations, or variations, which alters genetic instructions.

Researchers are discovering that specific genetic variations predispose individuals to certain decision-making behaviors. For example, some variations in the gene MAOA (monoamine oxidase) are associated with aggressive and compulsive behavior (thus the nickname warrior gene), or a susceptibility to psychiatric disease, including pathological gambling. MAOA is an enzyme that regulates the metabolism (breakdown) of complex molecules into simpler ones, including neurotransmitters such as serotonin and dopamine. Neurotransmitters, in turn, also play a role in decision-making.

Genes such as MAOA can have more than one type of variation and each can influence behavior in different ways. For example, some forms of MAOA are associated with an increased propensity to take financial risks. Individuals with MAOA-L are better at making smart financial decisions even in risky circumstances.

In one study, scientists asked 90 males to make dozens of choices between pairs of monetary gambles. Men who had the MAOA-L variation were more likely to make riskier decisions. However, the researchers determined this was not necessarily a bad thing: when presented with these financial options, the men only engaged in riskier behavior when it was to their advantage to do so, and not simply because they were impulsive. In other words, they made better financial decisions despite the risks. This study was limited to a small number of participants and the differences in decision-making may have been due to, or influenced by, other factors such as intelligence or numerical ability.

In another small study of 26 individuals, researchers found that a genetic variation of dopamine predicted who would make quicker, more accurate decisions. It was not just the variation of dopamine, but also the way this neurotransmitter communicated between two critical areas of the brain related to decision making. Individuals with the dopamine variation had an advantage in performing tasks that required them to adapt their future expectations of rewards based on current reward schedules. This advantage might come in handy in gambling situations, for example.

While it might be tempting to blame your genes when you make particularly poor (or good) decisions, it's not that easy. Environmental factors also significantly influence decision-making.

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